The invention relates to a cleaning cloth having a nonwoven structure for wet, damp and/or dry cleaning.
Cleaning cloths are generally familiar, and are provided for removing dirt from the surface of an object and for taking up the dirt itself. To achieve both objectives, a cleaning cloth must have very good cleaning efficiency as well as sufficient abrasion resistance, and must be provided with ample pore volume, in order to store the dirt.
DE OS 30 35 038 deals with a cleaning cloth exhibiting good performance properties. It is made from porous microfibers of a polymer material which have an essentially non-porous fiber core and an open-pored, foamed fiber sheath. Such a cleaning cloth made of polymer material has particularly high mechanical resistivity, which has a positive effect with respect to resistance against wear. Improved resilience and enlarged bulk with improved soil pick-up capacity are achieved by a mixture of microfibers with staple fibers or filaments.
The U.S. Pat. No. 4,145,464 deals with another embodiment of a cleaning cloth. In that case, the cleaning cloth is produced from a mixture of cellulose and synthetic fibers, is covered on both sides by cellulosic layers, and is bonded by mutually bonding all the fibers in locally separate zones. However, such a cleaning cloth has inadequate mechanical stability, since the cellulose fibers have a relatively short length of less than 6.35 mm, resulting in unsatisfactory abrasion resistance. Following even a relatively brief period of use, fiber components can become detached and deposit in the form of dust-like particles or fuzz on the surface to be cleaned.
Furthermore, the European Patent 0 423 619 describes a cleaning cloth which is formed of a plurality of layers, and specifically of a layer made of synthetic filaments, so-called filament fibers, which has a layer of staple fibers mixed with natural fibers on at least one of its sides. The amount of natural fibers is stated at 15 to 70%. High stability is attained with this cleaning cloth, particularly due to the bottom layer or middle layer of synthetic filaments. However, the short natural fibers in the covering layer(s) lead to unsatisfactory abrasion resistance, similar to the case in the aforementioned U.S. Pat. No. 4,145,464.
The object of the invention is to provide a cleaning cloth for wet, damp and/or dry cleaning which exhibits high abrasion resistance and has large pick-up volume for the rubbed-off dirt. In addition, it should be as firm as possible, offer good cleaning efficiency and, moreover, be pleasant to handle.
The objective is achieved according to the invention in a cleaning cloth of the type indicated at the outset, in that the cleaning cloth is made from micro staple fibers of at least two different polymers, and from absorbent secondary staple fibers. In such a cleaning cloth, the high cleaning efficiency and stability of the micro staple fibers and their abrasion resistance are combined with the high absorbency of the secondary staple fibers. The secondary staple fibers are bound into the micro staple fibers and are securely retained therein.
The micro staple fibers are multi-component split fibers, particularly bicomponent split fibers. They are formed predominantly of polymers based on polyester and polyamide. A wide field of possible variants exists here. The split fibers or fibrillated fibers are preferably selected from the standpoints of economics and process engineering.
Before being split, the titer of the multi-component fibers lies at 1.7 to 3.0 dtex. The titer of the split fibers is below 1 dtex, preferably below 0.2 dtex.
Staple fibers produced from natural fibers, in particular from cellulose fibers, from cotton, from viscose, lyocell and/or other absorbent staple fibers such as polyvinyl alcohol fibers, are used as secondary staple fibers. The titer of the secondary staple fibers lies at 1.0 to 3.0 dtex. These extrusion-spun staple fibers are perceptibly firmer than customary natural fibers.
To achieve a pore volume which is as large as possible, it is beneficial if the cleaning cloth is formed from at least two superposed nonwoven layers. In this context, it is particularly favorable if one of the nonwoven layers is made of micro staple fibers and absorbent secondary staple fibers, and the other nonwoven layer is formed from polymer tertiary staple fibers, in particular from a thermoplastic and absorbent secondary staple fibers. This nonwoven layer, produced using tertiary staple fibers, is particularly voluminous. Thus, advantage is taken here of the high cleaning efficiency and abrasion resistance of the micro staple fibers on the one side of the cleaning cloth in conjunction with the exceptional volume of the tertiary staple fibers and of the secondary staple fibers on the other side of the cloth. The absorption capacity is increased by the secondary staple fibers. The particularly preferred exemplary embodiment provides for using a nonwoven layer made of polymer tertiary staple fibers and absorbent secondary staple fibers as a middle layer which is faced on each of its sides by a covering nonwoven layer made of micro staple fibers and absorbent secondary staple fibers. In this cleaning cloth, the two outer layers which come in contact with the object to be cleaned exhibit high abrasion resistance, while the middle layer has a particularly voluminous bulk with a high absorptive capacity. Staple fibers made of a polyamide, having a titer that is customary for such fibers and lies above the titer of the microfibers, are preferably used as tertiary staple fibers.
The preferred manner of producing a cloth made of a plurality of nonwoven layers is to first form individual nonwoven layers and to join them to one another. In this context, each nonwoven layer can already be provided with the secondary staple fibers. However, it is also possible to initially provide only the tertiary staple fiber layer with the secondary staple fibers, and to bring the microfiber layer onto it without secondary fibers, and to introduce the secondary staple fibers into the micro staple fiber layer(s) as well by needle-punching the layers together.
The individual nonwoven layers are joined together by needle-punching, tanglelacing (i.e., intermingling) or laminating. Such processes are known per se. Particularly good results are attained if the nonwoven layers are interconnected by spot-fusing. This yields an open-work surface which increases the cleaning power of the cloth. When working with spot-fusing, the individual nonwoven layers can be bonded through fusion zones, using heat and pressure. However, it is also possible to bond the surfaces of the cleaning cloth through fusion zones, particularly by calendering.
The mass per unit area of the cleaning cloth is generally 75 to 250 g/sqm, preferably 120 to 180 g/sqm. For a three-layer cleaning cloth composed of a middle layer made of tertiary staple fibers and secondary staple fibers, and two covering layers made of micro staple fibers and secondary staple fibers, the mass per unit area of the middle layer is selected such that it amounts to 40 to 80% of the total mass per unit area. In this case, it is beneficial if the masses per unit area of the covering layers are identical.
The portion of micro staple fibers in the covering layer(s) outweighs the portion of secondary staple fibers. The portion of micro staple fibers lies between 70 and 98%, preferably between 70 and 80%.
In the middle layer, the portion of secondary staple fibers outweighs the portion of tertiary staple fibers. It is between 70 and 100%, preferably between 70 and 80%.